This invention pertains to a curtain wall for use in a building exterior and more particularly to a silicone slab splice joint for preventing leakage between adjacent support members in the curtain wall.
Curtain walls are typically constructed of an aluminum frame support members which provide generally U-shaped channels for supporting a panel or sheet material which serves as the building exterior. The curtain wall panel material is often panes of glass but can be other exterior building materials such as aluminum, granite, slate, or concrete panels or the like. For simplicity in explanation only, the discription contained herein will pertain to a glass curtain wall.
The curtain walls are constructed of a plurality of horizontal aluminum support members which define an upwardly directed U-shaped channel, a downwardly directly U-shaped channel or both upwardly and downwardly U-shaped channels. These horizontal support members are held in place by vertical mullions which are interiorly of the horizontal support members.
Glass panels are supported in an upwardly directed U-shaped channel at the lower edge of the glass panel and in a downwardly directed U-shaped channel at the upper edge of the glass panel. The vertical joints between adjacent glass panels are sealed with a silicone sealant to prevent leakage between glass panels. Because the horizontal aluminum support members will expand and contract with temperature fluctuations, the joints between the adjacent horizontal members must allow for this expansion and contraction. The expansion and contraction is accomodated by providing a space between adjacent ends of the support members. Typically, the space between adjacent support members has been sealed with a conventional caulking material. Difficulties, however, have arisen in preventing leaks in that the effectiveness of the caulking to prevent leaks is relatively short lived. After a short number of expansion and contraction cycles and weathering, the caulking compound will crack and split to the point that it is no longer capable of preventing leakage between the support members.
Accordingly it is an object of this invention to provide an improved joint between adjacent horizontal support members in a curtain wall.
This is accomplished by molding a flat slab of silicone which is then placed in the support member U-shaped channel bridging the space between adjacent ends of the support member. The silicone slab is retained in place in the support member by means of a silicone sealant which is formed of essentially the same material as the slab. The slab forms a bridge between the adjacent support members thus preventing leakage therebetween. The superior quantities of the silicone material allow for numerous cycles of expansion and contaction of the joint without degrading the silicon material to the point which would allow leakage through the joint.
Further objects, features and advantages of the invention will become apparent from a consideration of the following description and the appended claims when taken in conjunction with the accompanying drawings.